This invention applies to the field of topical preparations.
One of the major problems experienced by skiers and others who spend long periods of time outdoors in cold weather is that of coldness in the extremities. After exposure to cold temperatures, the feet in particular become painful. Previously, the most common method of preventing cold feet has been to insulate the feet from the environment, such as by wearing insulated boots or additional layers of socks. Insulation, however, can be increased only to a limited degree, consideration being given to the comfort and mobility of the wearer. Further the feet will eventually become cold as the blood vessels of the feet constrict in order to retain heat in the rest of the body. The only solution, then, has been for the skier to return indoors.
Electric boot warmers and socks have also been used to prevent cold feet. These devices are battery powered, which limits their use over extended periods of time. A typical device, an electric heating pad sole for boots, does not provide enough heat for really cold conditions and supplies only short, five-minute bursts of heat, with a maximum cumulative operating time of only 90 minutes before the batteries must be recharged overnight. Use beyond the 90 minutes without recharging can result in permanent damage to the units.
Chemical reactions which release heat have also been used. These reactions, however, fade rapidly and can be dangerous to the skin.
Preparations which provide a sense of warmth to painful areas of the body are well known, and are generally based on counterirritants, substances which produce a superficial irritation in order to reduce irritation in adjacent structures. Such counterirritants commonly used in these preparations include capsicum oleoresin, methyl salicylate, turpentine, mustard, and camphor. A commercially available preparation, for instance, contains capsicum oleoresin, turpentine and petrolatum. These heat-producing preparations are recommended for treatment for muscle pain and arthritis, but are not associated with producing a sense of warmth apart from the treatment of pain.
A composition, known as "outdoor cream" is available for application to the hands and feet. This composition contains water, triethanolamine stearate, propylene glycol, cocoa butter, dimethicone, acetylated lanolin, magnesium stearate, glyceryl stearate, mineral oil, lanolin alcohol, PVP, methyl paraben, propyl paraben, and triclosan.